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From: Niels Blaauw <niels_at_nibla.nl>
subject: [Paddlewise] A new way to teach the forward stroke?
Date: Sat, 23 Apr 2011 23:07:34 +0200
I've been teaching the forward stroke for about ten years now. I think 
the stroke itself is fine, but my justifications  were shaky. I thought 
up a better explanation of why our normal forward stroke is the best. My 
explanation is at least consistent with the laws of physics, which can't 
be said for the explanations I've heard so far and used myself.

The summary of my thoughts would be: "take it easy: Use gravity". To 
explain more elaborate I need a paddle - so I made a 10-minute video 
about it:

http://www.youtube.com/watch?v=-aB0rdn4UnQ

I know that Paddlewise has some passionate paddlers and some people who 
know their physics. If any of you could spare 10 minutes to watch it and 
give me an informal peer-review, it would be much appreciated. I plan to 
use this explanation on my students this summer, so by proving me wrong, 
any one of you could save 20 people from ending up with a wasted evening.

Some notes on the video, to save myself from answering the questions 
afterwards:
- My native language is Dutch. Forgive me my funny accent, grammatical 
errors, and confusing "force" with "energy" in some cases. Especially 
that last error embarrasses me - just not enough to do it over.
- I'm talking strictly about a _touring_ stroke. My explanation does not 
apply to any competition-stroke.
- My examples of failing explanations, in the first minute of the video, 
may be strawmen. If so, please let me know.
- The last minute of the video is a product-placement. Since the product 
has never been sold, I hope you guys can forgive me.
- The occasional howling in the background is my faithful canine 
companion Kira. The outdoor-shots with her in the picture were cute 
enough to stitch together into a seperate video:
http://www.youtube.com/watch?v=4N85gqVvlWU

As I said: comments, arguments and corrections are most welcome.

Niels
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From: Niels Blaauw <niels_at_nibla.nl>
subject: Re: [Paddlewise] A new way to teach the forward stroke?
Date: Sun, 24 Apr 2011 17:58:58 +0200
Gerald Foodman wrote:
> In the video you call the power phase of the stroke the resting 
> phase.  This is incorrect and will mislead students.
I call it the resting phase, while you call it the power phase. Why 
would I be wrong, and not you? Tradition is not a valid argument.
>    Plus, very little energy is required to change sides, which again 
> is contrary to what is said in the video.
The energy to change sides amount to about 30 Nm in my case: I lift over 
3 kilograms about 1 meter in the air. If I do that every second, I put 
about 30 Watts into just lifing my arms. If that efficiently converts to 
forward power, I should give a kayak a speed of about 2.5 miles per hour 
(which is just below my normal touring speed), if the measurements from 
this site are correct:
http://www.oneoceankayaks.com/kayakpro/kayakgrid.htm#waveanch

Niels
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From: Niels Blaauw <niels_at_nibla.nl>
subject: Re: [Paddlewise] A new way to teach the forward stroke?
Date: Sun, 24 Apr 2011 19:41:49 +0200
Gerald Foodman wrote:
> It is called the power phase because that is when the power that moves 
> the boat forward is applied. 
Please note that I don't claim that lifting your arms is the _only_ 
source of power. As I explain in the video, there are many ways to add 
extra power - but using gravity is a good start.
> While changing sides, no power at all is applied to moving the boat 
> forward.
> I assume that most of the energy a paddler expends is to move the boat forward.  While changing sides, no paddler energy is moving the boat forward.
>    
Do you remember old-fashioned mechanical clocks? Those things used to 
have a weight to store energy. That weight would slowly move down, 
giving energy to move the pendulum and rotate the arms of the clock. My 
explanation builds on that same principle: That energy can be stored as 
potential energy, reclaimed when moved by gravity, and converted into 
force and movement. The main difference would be, that a clock needs its 
weight lifted once a day, while a paddler needs it lifted once a second.

Up till now, your arguments are easily refuted with a little knowledge 
of classical mechanics. I still value your comments, though. I will 
probably get the same comments from my own students and peers, and you 
give me a good chance to prepare my answers.

Niels
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From: Niels Blaauw <niels_at_nibla.nl>
subject: Re: [Paddlewise] A new way to teach the forward stroke?
Date: Mon, 25 Apr 2011 20:08:03 +0200
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From: Niels Blaauw <niels_at_nibla.nl>
subject: Re: [Paddlewise] A new way to teach the forward stroke?
Date: Tue, 26 Apr 2011 02:04:22 +0200
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From: Niels Blaauw <niels_at_nibla.nl>
subject: Re: [Paddlewise] A new way to teach the forward stroke?
Date: Tue, 26 Apr 2011 14:50:11 +0200
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From: Niels Blaauw <niels_at_nibla.nl>
subject: Re: [Paddlewise] A new way to teach the forward stroke?
Date: Thu, 28 Apr 2011 13:56:59 +0200
Gerald Foodman wrote:
 > I assume that most of the energy a paddler expends is to move the
 > boat forward.  While changing sides, no paddler energy is moving the
 > boat forward.  Hence, changing sides energy is small compared to the
 > power phase.

and:
 > The idea that the potential energy stored while lifting the arms is
 > then returned to move the boat forward is false [...]
 > [The] power must come from the paddlers muscles, and only after the
 > blade is fully immersed.

I made a little video with a mythbuster-like test, showing the validity 
of the principle:
http://www.youtube.com/watch?v=TIm_d3eqzak
I conclude that it IS possible to store potential energy in your arms 
and paddle, and use it to propel a kayak.

---------------------------------------

I feel a need to summarize the discussion so far:
We're talking about my youtube-video on the physics of the forward stroke:
http://www.youtube.com/watch?v=-aB0rdn4UnQ

Gerald Foodman wrote:
> In the video you call the power phase of the stroke the resting phase.
 > This is incorrect and will mislead students.

This was best answered by Carey:
 > I guess if you are the kayak, the arms moving down and back is the
 > "power" phase of the stroke, but if you are the arms, it would indeed
 > be the rest phase. So it becomes a perspective issue doesn't it? It
 > is both the power phase and the rest phase at the same time.

Gerald Foodman wrote:
 > Plus, very little energy is required to change sides, which again
> is contrary to what is said in the video.
I made the calculation: Up to 30 watts is stored and released by just 
lifting and lowering the paddle. Since 30 watts is what's needed to 
propel a kayak at about 2 miles an hour, I consider the amount of energy 
significant.

Gerald Foodman wrote:
 > Take two limiting cases.  First the wing stroke: [...] the upper arm
 > staying at the same level [...] the wrist near the immersed blade
 > also stays at the same level.
A random instruction video from youtube proves otherwise - as does my 
own video with my own stroke. I recalculated the energy of my own 
stroke, as seen in my own video. My hands and paddle, when resting on a 
scale,weigh about 7 kilos. During my stroke, I drop the paddle about 40 
centimeters. I lift and drop an arm every second - which comes close to 
the 30 watts I claimed earlier.

Gerald Foodman wrote:
 > Second case is a very low Greenland type stroke as taught, for
 > example, in Doug Van Doren's video.  Again there is very little
 > altitude change of the arms during the power phase.
The greenland stroke might be a completely different stroke - I don't 
know, I never studied it. It doesn't matter: I'm not talking about the 
greenland stroke.

I think that covers all objections so far. I'm hoping for more solid 
arguments: I was really hoping for a serious discussion on mechanics. I 
still MIGHT be wrong, even very wrong; but so far, I have no indication 
that I am.

Niels
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From: Niels Blaauw <niels_at_nibla.nl>
subject: Re: [Paddlewise] A new way to teach the forward stroke?
Date: Thu, 28 Apr 2011 18:29:12 +0200
Carey Parks wrote:

> I'm not able to make any statements about absolute efficiency of one
> stroke vs another, I'll leave that to you physics types.

If it were just physics, it wouldn't be that hard - but since there's 
physiology involved, we'd need to measure the oxygen-usage of paddlers 
with different strokes. Lacking that, we'd better not talk too much 
about efficiency, but about the ability to _keep it up_ for any length 
of time. Which is convenient, since both of us ARE talking about that. 
It's the main question in my video: "How _do_ we keep it up?"

> But I can't paddle like that all day. In fact, I can't paddle any
> particular way all day.

Neither can I, now that you mention it. Mostly, I don't WANT a single 
best stroke: Other strokes allow me better to enjoy the scenery, smoke, 
photograph and talk to my dog while paddling, and just feel more relaxed 
- which is what I paddle for.

The stroke I teach has a very specific purpose for me. Whenever I find 
myself late in the afternoon, hungry, tired, with just an hour of 
daylight left and 5 kilometers to paddle to the car, _this_ is the 
stroke I turn to get the job done.

> It is easy to demonstrate our muscles work best in pulses, not steady
> output. Just hold the paddle at arms length and see how long it is
> comfortable.

About 1 minute... I've tried.

> Yet we somehow manage to paddle for hours without
> "stopping" (if you are the kayak.)

When trying it, in my living room, I could keep it up longer if I moved 
the paddle in a paddling-like style. I could keep that up for perhaps 5 
minutes, but nowhere near an afternoon of paddling. There might be a 
placebo-effect involved though: I _wanted_ to keep it up for only a 
short time.

> I know I have several different
> strokes, some of which look the same from outside, but internally I can
> be pulling my low hand one time and pushing my top hand the next,
> sharing the work and allowing for some recovery.

Hmmm... I don't think I have different strokes that look the same. I'll 
check, next time on the water.

> So there may be physiological reasons to favor a stroke, or strokes,
> which are different from the pure mechanical advantage of one stroke vs
> another. I do use the "vertical rest stroke" every time I go out, but it
> is not the only stroke I use, and it probably isn't the one I use most
> during a 10 mile paddle.

"Vertical rest stroke"... I like it. ;-)

Niels
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From: Craig Jungers <crjungers_at_gmail.com>
subject: Re: [Paddlewise] A new way to teach the forward stroke?
Date: Thu, 28 Apr 2011 10:49:09 -0700
I haven't joined this discussion because if the transition to a GP has
taught me anything it's that I know nothing about paddling strokes.

But when Carey said, "But I can't paddle like that all day. In fact, I can't
paddle any
particular way all day." It sure struck a chord. Looking at Niels' video I
think that I sometimes paddle that way with a Euro paddle. As a resting...
low energy... stroke. I have no idea how efficient it is but it keeps the
kayak moving forward until I'm ready to change to a different stroke.

It's interesting to see how Niels has analyzed it and I can see that if you
think of the hardest effort of that particular stroke and call that the
"power" stroke, then lifting the paddle could, indeed, be the power stroke.
It's just that, at least in my hands, it's not all that powerful.

For me the most interesting part of this exchange is that it's easier to
paddle than to just hold the paddle up.  :)

Nice exchange of ideas. Thanks, Niels.

Craig Jungers
Moses Lake, WA
www.nwkaykaking.net & www.bigboxbikes.com
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From: Niels Blaauw <niels_at_nibla.nl>
subject: Re: [Paddlewise] A new way to teach the forward stroke?
Date: Thu, 28 Apr 2011 21:27:08 +0200
Craig Jungers wrote:
>
> For me the most interesting part of this exchange is that it's easier to
> paddle than to just hold the paddle up.  :)

Another observation that might be related: Did anyone notice that 
paddling has a _minimum_ speed? When paddling with novices, I often make 
just one or two strokes, and then just rest my paddle on the cockpit, 
waiting for the others to catch up. In my white-water boat, where 
resting the paddle makes me drift of course, I often use a canoe-like 
stroke, keeping my paddle on the left, exchanging the occasional stroke 
with a lazy rudder.

That minimum speed, is that just me, or does it have more victims?

Niels
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From: Craig Jungers <crjungers_at_gmail.com>
subject: Re: [Paddlewise] A new way to teach the forward stroke?
Date: Thu, 28 Apr 2011 12:48:10 -0700
On Thu, Apr 28, 2011 at 12:27 PM, Niels Blaauw <niels_at_nibla.nl> wrote:

>
>
> That minimum speed, is that just me, or does it have more victims?
>
> Definitely not just you! I find myself doing that a LOT when I paddle with
family members. They're all working hard and I am mostly drifting along with
a stroke here or there.

Back in my youth I taught tennis and noticed that as you get experience in
an activity and your muscles get trained you put forth much less energy than
someone new to that sport. Even in my 40s I could easily wear out new
players who were young and fit. Newbies would hit too hard, run too fast,
stop too soon, and generally squander their energy.

I suspect it works the same with kayak newbies. Although I tend to paddle
fast in general (at least according to Pam) I think that you're right. The
minimum speed is about 2.5 kts I think. :P

Craig Jungers
Moses Lake, WA
www.nwkayaking.net & www.bigboxbikes.com
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From: Niels Blaauw <niels_at_nibla.nl>
subject: Re: [Paddlewise] A new way to teach the forward stroke?
Date: Thu, 28 Apr 2011 22:06:46 +0200
Craig Jungers wrote:

> Back in my youth I taught tennis and noticed that as you get experience
> in an activity and your muscles get trained you put forth much less
> energy than someone new to that sport. Even in my 40s I could easily
> wear out new players who were young and fit. Newbies would hit too hard,
> run too fast, stop too soon, and generally squander their energy.

I think that in MOST activities, people learn by themselves to work as 
efficiently as possible. Not just tennis, but also walking, typing and 
scratching your head. So far, I agree with you, but...

 > I suspect it works the same with kayak newbies.

It seems that paddling is counter-intuitive. Left on their own, newbies 
will develop a very shallow, long stroke, with the paddle on their 
bellies. In time, their muscles will get trained to do it longer and 
more powerful, but it seems that we need instruction to get it right, 
contrary to most activities. I myself had been paddling for 20 years 
before getting instruction and adapting a decent stroke - if indeed I have.
(Which is not to say that other sports don't need instruction; just that 
running and efficiently turning come natural to most.)

> Although I tend to
> paddle fast in general (at least according to Pam) I think that you're
> right. The minimum speed is about 2.5 kts I think. :P

I think mine is at most 2 kts - but then again: I'm a sissy and I paddle 
a bathtub. My most comfortable speed is around 3 kts.
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From: Darryl Johnson <darryl_johnson_at_rogers.com>
subject: Re: [Paddlewise] A new way to teach the forward stroke?
Date: Thu, 28 Apr 2011 15:59:21 -0400
On 28/04/2011 3:27 PM, Niels Blaauw wrote:
> Craig Jungers wrote:
>>
>> For me the most interesting part of this exchange is that it's
>> easier to
>> paddle than to just hold the paddle up. :)
>
> Another observation that might be related: Did anyone notice that
> paddling has a _minimum_ speed? When paddling with novices, I often
> make just one or two strokes, and then just rest my paddle on the
> cockpit, waiting for the others to catch up. In my white-water boat,
> where resting the paddle makes me drift of course, I often use a
> canoe-like stroke, keeping my paddle on the left, exchanging the
> occasional stroke with a lazy rudder.
>
> That minimum speed, is that just me, or does it have more victims?
>
> Niels

I have a friend, ten years younger, bigger and stronger than me, who 
is a pain to paddle with. He contends that it is more tiring and just 
plain hard to do: to slow down to match my speed. So he scoots ahead 
and then rests every now and again while I catch up.

So there are at least two of you with a minimum speed fixation. <g>

-- 
   Darryl
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From: Jim <jimtibensky_at_fastmail.fm>
subject: Re: [Paddlewise] A new way to teach the forward stroke?
Date: Fri, 29 Apr 2011 08:42:02 -0500
Posted:   I have a friend, ten years younger, bigger and stronger than
me, who is a pain to paddle with. He contends that it is more tiring and
just plain hard to do: to slow down to match my speed. So he scoots
ahead and then rests every now and again while I catch up. So there are
at least two of you with a minimum speed fixation.




Count me as a third. I have a racing background and paddle hard a lot.
It is literally painful for me to paddle slowly. Fellow paddlers get
annoyed when I paddle circles around them, but it is a good way for me
to stay comfortable.


I can't add a lot to the forward stroke discussion but I will chime in.
Again, my background is racing, starting as a sprint racer, so my
forward stroke ideas may be skewed that way.

Some students understand and learn from technical explanations and some
can't stand them. For the techies the kind of analysis that has been in
this thread would be useful. I have, however, been able to teach and to
coach some very successful kayakers without ever getting too analytical
in the beginning. When I do get technical is in the process of
perfecting their natural stroke. Since people are put together
differently they will paddle differently. In my opinion. 

In the last century, I trained with the Polish champion sprinter Stefan
Kaplaniak (world champion in 1958). He is short, barrel-chested and has
very short arms. I am short, skinny, with very long arms. Movies (we
didn't have video in those days) of us paddling alongside each other
make it look like we are two different species. No similarities. All
this to say that what works for one may not for another.

My bottom-to-top way of analysis looks at what muscles kayakers have
that are well-developed and then asks why. Sprint racers, the forward
stroke specialists, have huge triceps, lats and quads. The tricpes
muscles extend the elbos, then pull the extended arm straight down, so,
if I am correct, sprint racers use a lot of energy pulling the blade
down. We always think in terms of 'rotation' but I think there is some
pull down as well. I think the triceps also lock the elbow in place
while the torso rotates, so maybe I'm wrong about the pull down. I also
think the triceps wouldn't be so big if gravity did most of the work.

My own teaching of the forward stroke emphasizes leg involvement to keep
the body and boat firmly connected and emphasizes torso engagement
through blending a sweep into a forward stroke
(http://www.paddlewise.net/topics/technique/forwardstroke.html). I
strongly agree with Matt that a good forward stroke should not be
vertical. Moving out away from the hull at the end of the stroke keeps
the blade in one's own wake, providing a nice solid resistance.

I guess I shouldn't turn this into a discussion of how I teach the
forward stroke, but, of all the details I am concerned with, using
gravity was never one of them. Now maybe I have another detail.

I've learned a lot from this thread and want to send my appreciation to
everyone to has contributed.

Thanks.

Jim Tibensky
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From: Niels Blaauw <niels_at_nibla.nl>
subject: Re: [Paddlewise] A new way to teach the forward stroke?
Date: Fri, 29 Apr 2011 20:07:54 +0200
Jim wrote:

> Count me as a third.

Fourth or fifth, actually. :-)

  I have a racing background and paddle hard a lot.
> It is literally painful for me to paddle slowly. Fellow paddlers get
> annoyed when I paddle circles around them, but it is a good way for me
> to stay comfortable.
Do they ever ask you to circle the other way round, so they won't get 
dizzy? I asked that of an ice-skater once. She tried, but couldn't: 
She'd only learned to turn left.

> Some students understand and learn from technical explanations and some
> can't stand them. For the techies the kind of analysis that has been in
> this thread would be useful. I have, however, been able to teach and to
> coach some very successful kayakers without ever getting too analytical
> in the beginning.

I don't get technical either during my sessions, for 2 reasons:
- 99% of my audience won't understand;
- ALL of my audience has come to PADDLE and not to listen to physics.

However, I think that what little I tell them should be based on solid 
facts. That's just me and my ethics: I don't like to mislead people, not 
even in their own interest. That's mostly why I bring the topic to 
Paddlewise: To check my facts.

During sessions, I want to give my students the simplest, shortest, most 
intuitive advice that I can, without straying from the facts. My usual 
advice (paddle vertical, keep it high, keep it far, rotate your torso) 
is already too much advice: I have to repeat it dozens of times before 
it starts to sink in.
If my vertical-rest stands up to scrutiny, it might be a very simple and 
fast way to teach the forward stroke: "Find the position of rest!" 
instead of "paddle vertical, keep it high, keep it far, rotate your torso."

  When I do get technical is in the process of
> perfecting their natural stroke. Since people are put together
> differently they will paddle differently. In my opinion.

I agree. As I said in my video: "The concessions are your own to make."

> I've learned a lot from this thread and want to send my appreciation to
> everyone to has contributed.

I'm glad I'm not the only one enjoying this discussion.

Niels
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From: Niels Blaauw <niels_at_nibla.nl>
subject: Re: [Paddlewise] A new way to teach the forward stroke?
Date: Sat, 30 Apr 2011 00:26:15 +0200
Between all the greenland-, boogy-, rental-, racing and shallow-water 
strokes, we're in danger of forgetting what stroke I'm trying to talk 
about - so I did my homework.

On a DVD  I found a paddler with an (in my humble opinion) exemplary 
stroke. THIS is the stroke I'm talking about. THIS is what I want for 
myself and my students; THIS is what my calculations and models are 
based on.

The DVD in question is "Performance Sea Kayaking: The basics and beyond" 
by Kent Ford.

The video is on my own website, in a player that I've written myself. It 
allows for slowmotion, frame-by-frame and sliding through the frames. 
Play with the controls, and it explains itself. It seemed appropriate to 
use this player instead of youtube, so we can all disect this stroke 
frame by frame and analyze the movements and forces.

http://www.nibla.nl/tmp/paddlewise/ExampleStroke/

To anyone who thinks this stroke is wrong and I should instead teach a 
greenland/california/waterbike stroke, my answer is "No". Why not? 
Because I don't want to. Why I don't want to? I don't want to think 
about it. I'm still not done contemplating my ceiling and haven't even 
started on quantum mechanics. I have to draw a line _somewhere_. I can't 
study _everything_.
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From: Niels Blaauw <niels_at_nibla.nl>
subject: Re: [Paddlewise] A new way to teach the forward stroke?
Date: Thu, 28 Apr 2011 21:56:20 +0200
Carey Parks wrote:
> The slower you go, the more you approach holding the paddle out in front
> of you without moving. There is a most comfortable pace no doubt. And a
> most efficient pace too I would think, that may not be the same.

Hey! That was _my_ line! ;-)
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From: Niels Blaauw <niels_at_nibla.nl>
subject: Re: [Paddlewise] A new way to teach the forward stroke?
Date: Sat, 30 Apr 2011 19:24:57 +0200
rebyl_kayak_at_energysustained.com wrote:

> The figures [for estimating the power output at 100 watts]
> come from two sources. i) The NASA research quoted in chapter 2 of the
> classic text 'Bicycling Science' by Wilson, which includes rowing and
> cycling and shows them to be similar in power production. The NASA
> graphs suggest that 200 Watts is near the upper end of cycling power an
> average man might sustain for an hour or more, so 100W is quite
> conservative. ii) the other source is my personal experience in using a
> moderately loaded 200W electric bike to go to work each day through a
> traffic free park, and the same bike with the motor switched off to
> return from work. There seems to be little difference in my average
> speed in either case. The effort I put into cycling seems about
> comparable to the effort I put into seakayaking with a speed of 7km/hr
> in a moderately loaded kayak in 1m waves and headwinds less tan 10knots.

I find it hard to believe that the power output of cycling or rowing can 
be matched by kayaking. Cycling uses the biggest, strongest muscles you 
have. Rowing (at least in a sliding chair) uses those same muscles and 
adds the muscles that stretch the back, which are again quite big.
Kayaking, compared to that, is little more than squirming your torso and 
flailing your arms.

But that's just belief, and we shouldn't talk about beliefs. For now, I 
accept that you output 100W of useful energy. The storage and usage of 
potential energy might be up to 1/3 of that output.

> PeterO response - I think blade turbulance leading to thermal losses
> could also be a factor but don't know to what extent.

There will _absolutely_ be losses in blade turbulance. But those losses 
are AFTER the conversion of potential energy to force and motion of the 
paddle blade. Those losses will exist in any stroke.

> The point I'm getting to re muscle tension is that its always there in a
> typical paddling stroke and I doubt its completely absent even in a limb
> that falls free, unless its anaesthetised perhaps.

As far as I know, only trained dancers can really let a limb drop 
freely. In the vertical-rest though, the arms do not fall free: Their 
speed is kept in check by the blade in the water. Even the arm of a 
non-dancer should have time to relax.

> But then I paddle at sea and it may be different on rivers.

My usual training sessions are in a pond, with mostly flat water. I'm 
sure that at sea you'll use much more muscles, to keep yourself balanced 
and keep your blade in the water. The excitement of being on waves will 
probably cause a lot of tension too - but all those tensions will be 
there whatever stroke you use.

> Response - There are detailed tables for oxygen and energy use at rest
> and in different activities in the 'Bicycling Science text but they
> don't include static tension - I'll have to look that up, unless someone
> has these figures already.

I've studied one of those tables - but it indicated that, at rest, a man 
consumes 750 watts of energy. All other sites claim it to be about 100W, 
so I don't trust the table I used.

I might find time tonight to do some heartrate measurements on myself: 
at rest, at light exercise and at holding a paddle in front of me. It 
might give _some_ insight in what's going on. I don't make a promise 
though: There might be a good movie on TV.

> Thanks for your patient responses Niels I've got a better uunderstanding
> of your ideas and techniques and though they may not be applicable to my
> circumstances they've improved my understanding of paddle strokes and
> been most interesting.

You're welcome. Your questions are friendly and curious; It's a pleasure 
to answer them.

Niels
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